When Nintendo releases a new IOS version, except for unusual circumstances (for example security updates to block homebrew), the new IOS does not replace any IOS already installed.
Instead, it gets installed in addition to any current IOS versions.
and not to be confused with "i OS", the operating system of Apple's i Phones and i Pads), which run on a separate ARM architecture processor to other Wii software (nicknamed Starlet by the Wii homebrew community, as it is physically located inside the graphics chip, the Hollywood, so it is a small part of Hollywood.).
With downloaded software, this should not theoretically happen, as the user cannot access the shop to download software unless the player has all the IOS versions that they require.As usual, Nintendo describes the update as: June 21, 2010 Wii Menu 4.3 Unauthorized Modifications Because unauthorized channels or firmware may impair game play or the Wii console, updating to Wii Menu version 4.3 will check for and automatically remove such unauthorized files. The only thing that will drive people to install this update will be the broken Shopping channel and hypothetical future games which will come with this update on disc.In addition, there are some behind the scenes enhancements that do not affect any prominently-used features or menus but will improve system performance. Anyway, here’s the technical changelog — much of this can be seen in the last few Wiimpersonator reports.We’re currently working on new exploits and a new release of the Hack Mii installer but we’ll spend some more time to obfuscate our exploits this time to make it harder for ninty to find and fix them.It might therefore take some more time until our next release.